U.S. patent number 4,006,267 [Application Number 05/525,233] was granted by the patent office on 1977-02-01 for color highlighting process.
This patent grant is currently assigned to Xerox Corporation. Invention is credited to Philip Kurz, deceased, by Jessie M. Kurz, executrix.
United States Patent |
4,006,267 |
Kurz, deceased , et
al. |
February 1, 1977 |
**Please see images for:
( Certificate of Correction ) ** |
Color highlighting process
Abstract
Conversion of selected image portions of a black and white
xerographic copy into color portions is accomplished by applying a
donor sheet, having a colorant in a resin binder coated thereon, to
the image portions and thereafter heating the donor. Upon stripping
the donor from the xerographic copy, the toner in the image
portions of the xerographic copy acquire a surface layer of the
colored composition from the donor sheet thereby resulting in a
color highlighting of the image. The use of a nonthermoplastic
binder resin material having a melting point of above 250.degree. F
is necessary to insure the nontransfer of the color composition to
background areas of the xerographic copy.
Inventors: |
Kurz, deceased; Philip (LATE OF
Columbus, OH), Kurz, executrix; by Jessie M. (Rockhill,
SC) |
Assignee: |
Xerox Corporation (Stamford,
CT)
|
Family
ID: |
24092443 |
Appl.
No.: |
05/525,233 |
Filed: |
November 19, 1974 |
Current U.S.
Class: |
430/47.1 |
Current CPC
Class: |
G03G
5/12 (20130101); G03G 13/01 (20130101) |
Current International
Class: |
G03G
5/12 (20060101); G03G 13/01 (20060101); G03G
013/00 () |
Field of
Search: |
;427/24,55,56,146,148,153,342 ;8/2.5,2 ;355/17 ;96/1R,1.2 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Pianalto; Bernard D.
Claims
What is claimed is:
1. A method of color highlighting an image portion of a xerographic
copy comprising:
a. applying a colored transfer donor including a substrate and a
layer of colorant in a nonthermoplastic resin binder in
face-to-face contact with an image portion of a xerographic
copy;
b. thermally activating the xerographic image by causing it to be
heated for 5 to 60 seconds within a temperature range of from about
130.degree. to 250.degree. F; and
c. removing the transfer donor to transfer the color of the donor
layer to the image portion of the xerographic copy.
2. The method of claim 1 wherein the colorant is a pigment.
3. The method of claim 1 wherein thermal activation occurs by
applying heat to the transfer donor.
4. The method of claim 1 wherein thermal activation occurs by
heating the xerographic copy.
5. The method of claim 1 wherein the substrate is a flexible
elastomeric material.
6. The method of claim 1 wherein the nonthermoplastic resin has a
melting point above 250.degree. F.
7. The method of claim 1 wherein the nonthermoplastic resin is
selected from the group consisting of polyvinylpyrrolidone and
substituted cellulose ethers.
8. The method of claim 7 wherein the nonthermoplastic resin is
polyvinylpyrrolidone.
9. The method of claim 8 wherein the pigment and binder are in a
weight ratio of from about 40/1 to 5/1.
10. The method of claim 9 wherein the weight ratio of
pigment/binder is 20/1.
Description
BACKGROUND OF THE INVENTION
This invention relates to methods of making color copies by a
thermal color transfer process and more particularly to methods of
producing color highlighted original documents from xerographic
copies.
The manner of obtaining an electrostaticallly imaged copy is well
known in the prior art and may be carried out in several ways; for
instance, it is described in U.S. Pats. Nos. 2,397,691 and
2,357,809 to Carlson. The method generally followed comprises: (1)
electrostatically charging a photosensitive plate; (2) imaging the
charged plate by means of actinic radiation which results in
dissipation of the charge in the exposed area and an electrostatic
image in the unexposed portions of the plate; (3) developing the
latent electrostatic image with a pigmented resin powder carrying
an opposite electrostatic charge to that on the latent images
whereby the powder is attracted and held in image form on the
charged area; (4) transferring the image from the imaged plate to a
copy sheet by mechanical or electrical means; and (5) fixing the
powdered image on the copy sheet by means of heat or chemical
treatment.
In U.S. Pat. No. 3,057,720 to Hayford et al., a method for
xerographic color reproduction is disclosed. In xerographic
reproduction the same basic xerographic steps as outlined above are
utilized in combination with the well known subtractive principle
of mixing primary colors. According to this principle, three
primary colors; namely, green, red and blue, are reproduced by
mixtures of the three complementary colors, referred to as
subtractive primary colors; namely, magenta, cyan and yellow.
According to this subtractive system, a magenta colored material is
characterized by a substantially complete absorption of the primary
color green and thus may be designated as green negative; cyan
material characterized by substantially complete absorption of the
color red; and a yellow material is characterized by a
substantially complete absorption of the primary color blue.
Utilizing this principle along with the basic xerographic process
outlined above, three primary color exposures and three
complementary color developments in registration will result in a
full-color xerographic reproduction. This process is more fully
outlined in the subject patent to Hayford et al.
The introduction of color xerography has made the production of
color copy possible. Therefore, the option of reproducing a color
original or making a color copy by limiting or changing development
sequence are both possible. Therefore, a typewritten letter may be
copied to have the typed characters appear green, red or blue.
However, the only means presently available for reproducing some
designated portion of an original in color (i.e., highlighting) is
to have a color highlighted original. In the case of typewritten
letter copy, this is significantly difficult and cumbersome
inasmuch as certain letters or words would have to be typed in a
color while others appear black and white.
Generally, the formation of color highlighted originals for use in
color xerographic reproduction processes requires some means of
transferring color to a given area of a document. In the case of a
typewritten page, a transfer sheet, in the form of a tape or strip,
having a flexible foundation and a coating of transferable material
comprising essentially a wax-like vehicle having suspended therein
a colorant and the original sheet are superimposed and subjected to
a localized imaging force in the form of pressure or heat. When
using a stripping material having a sheet of a transferable color
composition, there is difficulty in isolating compatible and
discrimminating materials which will color designate or print
portions as desired. Otherwise, the color portions will transfer to
undesirable areas such as the background area of a letter. In the
case of a typewritter force utilizing a tape, such a procedure is
cumbersome and time consuming.
The present invention relates to a color producing material
employed to highlight image portions of a xerographic copy so that
a color highlight original is available for xerographic color
reproduction.
SUMMARY OF THE INVENTION
According to the present invention a colored donor is provided for
thermal application to an image portion of a xerographic copy for
purposes of color highlighting said portion. The colored donor is
generally in the form of a sheet strip which includes a coating of
a colorant in a nonthermoplastic resin binder material. The coating
composition of the donor is applied to the surface of a portion of
a xerographic copy in face-to-face contact so that upon heating a
bond is formed between the tackified toner imaged area of the
xerographic copy and the color coating on the donor. The toner
imaged area of the xerographic copy having been made actively
adhesive by heating adheres to the color coating of the donor with
the result that when the donor is removed or stripped from the copy
sheet the image portions of the xerographic copy adhesively cling
to the colorant coating of the donor thereby resulting in a color
layer formation on the image portion of the copy.
In summary, the present invention relates to a method of color
highlighting an image portion of a xerographic copy comprising: (a)
applying a colored transfer donor including a colorant and a
nonthermoplastic resin binder in face-to-face contact with an image
portion of a xerographic copy; (b) thermally activating the
xerographic image; and (c) removing the transfer donor whereby the
color is transferred to the image portion of the xerographic
copy.
In one embodiment of the instant invention a donor sheet comprising
a layer of elastomeric material and a coating of a colorant in a
polyvinylpyrrolidone film forming resin binder is provided. The
colorant coating of the donor strip is placed face to face together
with a portion of an image of a xerographic copy. The sheet of
paper bearing the xerographic image is heated while the coated
donor sheet is pressed into contact with the image. Alternatively,
the stripout donor may be "ironed" with a hot iron onto the
xerographic image. In either case, the heating is maintained for a
period of between 5 and 60 seconds while the temperature is kept
between about 130.degree.-250.degree. F. Subsequently, the donor
sheet is stripped from the xerographic copy whereby the colorant
resin composition remains behind on the image portions of the
xerographic copy resulting in a color highlighted image.
BRIEF DESCRIPTION OF THE DRAWINGS
Additional features and advantages of the present invention will
hereinafter appear in the following drawings:
FIG. 1 is a diagrammatic perspective illustrating the electroscopic
powder image formed on a plate with a donor sheet being placed
thereon.
FIG. 2 is a diagrammatic perspective illustrating the transfer of
the colorant composition from the donor onto the imaged portions of
the xerographic copy.
FIG. 3 is a diagrammatic section illustrating the highlighted image
including the colorant composition bonded to the toner image.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring now to the drawings in which like reference numbers refer
to the same part and particularly to FIG. 1, the visible
electrostatic image has been formed on a substrate 11 such as
paper. A donor sheet 13 having a layer of coloring composition 14
hereinafter referred to as a transfer layer is superimposed over a
portion of the xerographic copy. Within the purview of the present
invention the colored layer 14 of donor sheet 13 is compatible with
the toner 12 of the imaged surface to the extent that it will
adhere to the surface of the tackified toner image and be removed
therewith when heat is applied and the transfer sheet is separated
from the xerographic copy 11.
The slight compatibility of the electroscopic powders or toners for
the transfer donor color coating is due in part to the adhesive
characteristics of the powders which are thermoadhesive resins such
as rosin, gum copal, gum sandarac, cumarone-indene resin, the
treated pine resin sold under the trademark "Vinsol" resin, ethyl
cellulose or Egytian asphalt or any other material which has the
required electroscopic properties. Moreover, the above-named
materials in the presence of a thermal activating means will become
tacky and bond to the transfer layer 14 of the donor sheet.
As mentioned above, according to the instant process a sheet of
paper bearing a xerographic image or images is heated while a
coated donor sheet bearing a stripable layer of colored composition
is pressed into contact with the image. Alternatively, the stripout
donor sheet may be "ironed" with a hot iron onto the xerographic
image and thereafter stripped. To insure transfer of color to the
xerographic image only, with no coloration of background or
nonimage areas, it is necessary that the donor coating not melt in
the range of temperatures utilized in the process. Generally,
temperatures of from about 150.degree.-250.degree. F. are utilized
in the process of this sort and therefore the coating composition
should not melt in this range. To this end it is essential that the
binder in the colored donor coating be nonthermoplastic and have
only a limited compatibility with the thermoplastic components of
the xerographic toners. The latter feature is necessary to minimize
intermelting and depreciable change in the color of the donor
coatings as it intermixes with the carbon black in the toner
image.
As is demonstrated above the transfer color coating on the donor
includes a colorant, in the form of a pigment or dye, in
combination with a resin binder material. Binder materials having
the requisite melting characteristics and limited compatibility
include polyvinylpyrrolidone (PVP), vinyl butyral resin,
substituted cellulose derivatives, and vinyl chloride-vinyl acetate
copolymer resins. The cellulose derivatives include the cellulose
ethers, ethyl cellulose, hydroxypropyl cellulose, and ethyl
hydroxyethyl cellulose. Optimum results have been achieved with
polyvinylpyrrolidone (PVP) as the film forming binder. Four
different grades of PVP ranging in molecular weight from 10,000
PVP-H15, 40,000 PVP-830, 160,000 PVP-K60, and 360,000 PVP-K90, all
supplied by General Aniline & Film Corporation, have been used
with essentially identical excellent results as binders. It has
been found that thermal stripout donor sheets based on PVP exhibit
a wide "window"; that is, neither the temperature nor the time
involved in the thermal transfer process is critical. For example,
excellent color highlighting results whether the temperature of
transfer is as low as 180.degree. F. or as high as 220.degree. F.
and transfer times are as short as 6 seconds or as long as 60
seconds. It has also been found that in no case will the
highlighting material transfer to paper inasmuch as the PVP binder
is nonthermoplastic.
The colorant used in combination with the binder in the coating on
the transfer donor may be any type of colorant which effectively
colors or tints the portion of the xerographic image to which it is
applied. Among the colorants which may be used include pigments
such as Ultramarine Blue I-805, ferricoxide (Fe.sub.2 O.sub.3),
chrome green light, ferro yellow, and cadmium lithopone. These
pigments may be lightened in shade by a mixture with titanium
dioxide pigment. Another form of colorant that may be used within
the purview of the present invention is dyed titanium dioxide. A
complete listing of colorants is outlined in the examples.
The suitable activating means within the purview of the instant
invention is the use of overall heat as for instance provided by a
hot plate, heated rollers, heat lamps or an "ironing" process.
According to this aspect of the instant invention, the heat
provided should be sufficiently high to soften the electroscopic
resin images and fuse them to the colorant coating on the donor,
but not sufficiently high to melt the color coating composition. In
general, temperatures within the range of 120.degree. to
220.degree. F. are satisfactory. However, the higher temperatures
are preferred (for instance, in excess of about 190.degree. F.) in
order to render the toner images very tacky and enhance their
adhesive attraction for the colorant coating layer on the donor. As
mentioned above, because such temperatures are used it is necessary
to use certain resin binder materials in the color coating
layer.
The amount of pigment to be utilized in the transfer donor color
layer is not critical within the purview of the present invention.
Therefore, it has been found that pigment/binder weight ratios may
range from about 5/1 up to about 40/1. A preferred ratio is about
20/1.
In the actual practice of the instant invention, the donor transfer
sheet 13 is applied to a selected portion 12 of a xerographic copy
11 as shown in FIG. 1. Heat is then applied either to transfer
donor 13 by means of "ironing" or the xerographic copy itself is
heated. After the image on the surface of the transfer donor sheet
has become sufficiently tacky, the transfer and donor sheets form
an adherent bond between the color coating layer 14 and the toner
image 12 on the xerographic copy. Upon removing or stripping donor
element 13 from the effected xerographic portion a highlighted
image results as is illustrated in FIG. 2. A portion of the color
coating is completely removed corresponding to the portion of the
xerographic image which is highlighted by color.
As previously demonstrated, under the effects of heat the
electroscopic toner images become tacky due to the absorption of
the heat and fuse to the color coating of the donor which is in
face-to-face contact with same. Upon separation or stripping of the
donor from the xerographic image, an excellent color highlighted
original sheet is provided as exemplified in FIG. 3 of the drawing.
Note that the color composition forms an independent layer upon the
electroscopic toner material thereby rendering it color highlighted
in the image areas.
Regarding the substrate to be used for the color coating 14 of the
transfer donor 13, any material may be utilized to accomplish the
purpose of transferring the color composition. Generally, flexible
materials such as paper and elastomeric resins are preferred. Most
appropriate are polyester and polycarbonate films such as Mylar,
manufactured by duPont Corp. and Lexan, manufactured by the General
Electric Co.
As mentioned above, generally a small amount of pressure is applied
between the donor and the xerographic image to which it is applied.
The amount of pressure necessary to accomplish sufficient bonding
will vary also depending on many factors such as the particular
coating on the donor, the conditions of the tackified image, the
particular toner material employed, a delay before placing the
softened and tacky toner image into the pressure assembly, humidity
and other atmospheric conditions, and the like.
DESCRIPTION OF SPECIFIC EMBODIMENTS
I. Preparation of Coating Mixtures
Coating mixtures for preparing donor sheets for thermal transfer
color highlighting are generally prepared by utilizing a shaker to
disperse the pigment or by milling the components. In the case of
milling it is sufficient generally to mill the pigments for 10 to
20 minutes in a device such as a paint shaker using a metal can to
confine the components of the mixture and stainless steel balls to
provide attrition. When a ball mill is used usually at least 4
hours of milling is recommended. In preparing the coating it is
preferred to dissolve the binder listed below in the
solvent-vehicle before mixing with the pigment. Typical coating
mixture compositions are in parts by weight and are as follows:
__________________________________________________________________________
Dyed-Resin Fluorescent Pigments Pigment/Binder Ratio 40/1 20/1 10/1
5/1 PVP-K90 (binder) 0.5 1 2 4 HI-VIZ Strong Red B2836 (pigment) 20
20 20 20 Ethanol (solvent-vehicle) 56 56 48 48 Pigment/Binder Ratio
18/1 9/1 PVP-K90 (binder) 1 1 Radiant Red P1600-515 (pigment)* 18 9
Ethanol (solvent-vehicle) 36 18 Pigment/Binder Ratio 9/1 PVP-K90
(binder) 1 Radiant Magenta P1700-618 (pigment) 9 Ethanol
(solvent-vehicle) 18 Pigment/Binder Ratio 100/1 49/1 10/1 9/1
PVP-K90 (binder) 1 1 1 1 Radiant Pink P1700-617 (pigment) 100 49 10
9 Ethanol (solvent-vehicle) 200 98 20 18 Pigment/Binder Ratio 50/1
Vinylite XYHL (binder) 1 HI-VIZ Magenta B2854 (pigment) 50 Ethanol
(solvent-vehicle) 86.5 Pigment/Binder Ratio 9/1 Vinylite XYHL
(binder) 1 HI-VIZ Strong Red B2836 (pigment) 9 Ethanol
(solvent-vehicle) 18 Pigment/Binder Ratio 9/1 Ethylcellulose N-10
(binder) 1 HI-VIZ Strong Red B2836 (pigment) 9 Ethanol
(solvent-vehicle) 18 Pigment/Binder Ratio 9/1 Klucel J (binder) 1
HI-VIZ Strong Red B2836 (pigment) 9 Ethanol (solvent-vehicle) 18
Mineral Pigments (Undyed or Dyed) Pigment/Binder Ratio 9/1 PVP-K90
(binder) 1 Ultramarine Blue I-805 (pigment) 9 Ethanol
(solvent-vehicle) 18 Pigment/Binder Ratio 20/1 PVP-K90 (binder) 1
Titanium Dioxide (pigment) 15 Cyan Green Toner 15-3100 (pigment) 5
Ethanol (solvent-vehicle) 40 Pigment/Binder Ratio 17/1 PVP-K90
(binder) 1 Titanium Dioxide (pigment) 10 Cyan Green Toner 15-3100
(pigment) 5 Ultramarine Blue I-805 (pigment) 2 Ethanol
(solvent-vehicle) 40 Pigment/Binder Ratio 17/1 PVP-K90 (binder) 1
Titanium Dioxide (pigment) 10 Ferric Oxide (pigment) 5 Ultramarine
Blue I-805 (pigment) 2 Ethanol (solvent-vehicle) 40 Pigment/Binder
Ratio 10/1 15/1 20/1 PVP-K90 (binder) 1 1 1 Titanium Dioxide
(pigment) 10 15 20 Alphazurine 2G (dye) 1 1 1 Ethanol
(solvent-vehicle) 40 40 40 Pigment/Binder Ratio 10/1 10/1 15/1
PVP-K90 (binder) 1 1 1 Titanium Dioxide (pigment) 10 10 15 Calcocid
Phloxine 2G (dye) 1 1.5 1.9 Acid Magenta 0 1 0.5 0.1 Ethanol
(solvent-vehicle) 40 40 40 Dyed Nonfluorescent Organic Pigments
Pigment/Binder Ratio 20/1 PVP-K90 (binder) 1 Geon 135 (pigment) 20
Brilliant Blue J (dye) 0.25 Ethanol (solvent-vehicle) 40
Pigment/Binder Ratio 20/1 PVP-K90 (binder) 1 Geon 135 (pigment) 20
Calcocid Phloxine 2G (dye) 0.25 Ethanol (solvent-vehicle) 40
__________________________________________________________________________
*Radiant Blue P1600-519 and Radiant Green P1600-511 also used in
place of Radiant Red P1600-515 in 18/1 and 9/1 mixtures.
II. Preparation of the Donor Sheets
The coating mixtures, prepared as described above, were used to
coat 2-mill Mylar sheets which serve as substrate supports for the
donor coatings. In the coating process, a bead of coating mixture
was applied to the horizontally positioned sheet near one end.
Then, with a wire wound draw down rod (numbers 14, 24, and 36 were
used) the coating mixture was spread over the length of the sheet.
In the case of ethanol as the solvent vehicle it was found that air
drying of the coatings for 20 minutes at room temperature was
sufficient.
III. Thermal Transfer
The colored donor sheets prepared as described above can be used in
two modes of thermal transfer processes to produce a color
highlighted xerographic image. In the first mode the donor sheet is
pressed against a heated sheet of paper bearing a xerographic
image. In this process, the xerographic copy is generally placed on
a source of heat such as an electric hot plate which is regulated
at temperatures between 180.degree.-220.degree. F. In the second
mode, the paper bearing the xerographic image is placed on a
flexible support, covered with the donor sheet prepared above, and
heat is applied through the back of the donor by means of an
electrically heated iron operated at between temperatures of
150.degree.-220.degree. F. In both cases separation of the donor
material from the xerographic image results in a color highlighting
of that portion of the xerographic copy. The main differences
between the two is that heating the xerographic copy generally
results in quicker transfer, i.e., in 1 second or less. Transfer is
achieved from 7 to 10 seconds utilizing the iron to heat the back
of the donor.
While the present invention has been described and carried out in
terms of specific embodiments thereof, it is not the intention to
be so limited thereby, but is intended to cover the invention
broadly within the spirit and scope of the appended claims.
* * * * *